The chumash are genetically very close to other American Indian peoples, who are collectively related to historic groups that populated Northeast Asia. Both land and sea voyages from Asia to the Americas are reasonable mainstream hypotheses given current evidence, but they're both commonly called "crossing the Bering strait".

A transpacific voyage from somewhere like southeast Asia may have been theoretically possible, but there's no actual evidence that the first settlers of the Americas came that way and quite a lot of evidence that they didn't.